certification authority (CA)

1. Internet commerce: Trusted third-party (a bank or a firm such as VeriSign) that issues digital certificates under a public-key infrastructure (PKI) to guaranty that the two parties to a transaction are who they claim to be. CA authenticates a user's identity and creates a public-key for message encoding (encryption), and a private-key for message decoding (decryption). Each certification authority has its own identification requirements and validation procedures for issuing certificates, such as driver's permit, passport, fingerprints, notarized declaration, or other documents. Usually, different certificates with different levels of security are issued to suit different user requirements; for example, VeriSign has four classes of certificates with Class-1 having the lowest level of confidence and Class-4 the highest.

2. Products: Firm (such as Underwriters' Laboratory) that allows its certification mark to be used on the goods manufactured by other firms.